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< 12. Troubleshooting >
12-6
IM 11M12D01-01E
12.2 Displays and Remedies When Alarms are
Generated
12.2.1 Alarm Types
The following types of alarms may be generated by the averaging converter. If an alarm is generated,
actions such as turning off the heater power are not carried out. The alarm is canceled when the
cause of the alarm is removed.
Alarm 5 (cold junction temperature alarm) may be generated concurrently with Error 2 (heater
temperature error). In this case, the operation when the error occurs has priority.
If the power to the averaging converter is turned off after an alarm is generated and the averaging
converter is restarted before the cause of the alarm has been removed, the alarm will be generated
again. Alarms 2, 3 and 4 (related to calibration) are not generated unless calibration is executed.
An alarm will be automatically canceled after the cause of the alarm is removed.
Table 12.2 Alarm Types and Occurrence/Cancellation Conditions
Alarm
Code
Alarm Type
Occurrence/Cancellation Conditions
Unit to be
detected
Alarm 1 Oxygen
concentration
alarm
Measured oxygen concentration value exceeds or falls below the
preset alarm limits. For details, see Section 8.2, “Setting Oxygen
Concentration Alarms.”
Each channel
Alarm 2
Zero calibration
coefficient alarm
In Auto or Semi-auto calibration, zero correction ratio is outside the
range of 100 ± 30%. See Subsection 9.1.3, “Compensation.”
To stop alarm: Recalibrate and stops if the ratio falls within the range.
Each channel
Alarm 3
Span calibration
coefficient alarm
Span correction ratio is outside the range of 0 ± 18%.
See Subsection 9.1.3, “Compensation”
To stop alarm: Recalibrate and stops if the ratio falls within the range.
Each channel
Alarm 4 Calibration time over
(EMF stabilization
time-up) alarm
In Auto or Semi-auto calibration, cell voltage does not stabilize for
1 minute even after calibration time is up. Stabilization means that
margin of cell voltage fluctuation is within ±0.1 mV and the state
continues for about 1 second.
To stop alarm: Recalibrate and stops if the stabilization time falls
within the normal range.
Each channel
Alarm 5 Cold junction
temperature alarm
Temperature of the cold junction placed in the detector terminal box
falls below -25°C or exceeds 155°C.
To stop alarm: The cold junction temperature becomes a normal
value.
Each channel
Alarm 6
Process gas alarm
Averaging converter receives a signal of process gas alarm at
contact input.
To stop alarm: Contact input signal of process gas alarm is removed.
System
Alarm 7
Calibration gas
pressure low alarm
Averaging converter receives a signal of calibration gas pressure low
alarm at contact input.
To stop alarm: Contact input signal of calibration gas pressure low
alarm is removed.
System
Alarm 8 Asymmetry alarm
Calibration coefficient unstable. Alarm output if alarm enabled and
conditions in Subsection 12.2.3, 7) are satisfied.
Each channel
Alarm 9
Inside temperature
alarm
Internal temperature of the case exceeds limit. The limit is about
50°C in terms of case ambient temperature. Occurrence/cancellation
time is recorded.
To stop alarm: If the internal temperature falls below the limit.
System
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